The increased faecal PAI-1 level correlated with the endoscopic activity [r = 0.5501, p <0.0001; Figure 6E], whereas ROC curves demonstrated that faecal PAI-1 showed a relatively high power to distinguish between active and inactive IBD patients [AUC = 0.82; specificity: 80%; sensitivity: 74%; cut-off: 0.6 ng/g; Figure 6F] and between controls and active IBD patients [AUC = 0.83; specificity: 62%; sensitivity: 88%; cut-off: 0.2 ng/g; Figure 6G]. This evidence concerns the gene SERPINE1 and irritable bowel syndrome.